Multi-zone fracturing shifter with full wellbore access
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Solution Overview
Problem
In wellbore completion operations, multi-zone fracturing is inefficient due to the need to mill out obstructions formed by dropped balls used to actuate sliding sleeves, leading to lost time and reduced productivity.
Innovation Solution
A system and method using a single shifter device on coiled tubing to selectively open multiple sleeve assemblies along a wellbore, allowing for fracturing operations without the need to mill out obstructions, by collapsing a baffle to expose fracturing ports and maintaining a full inner diameter, facilitating efficient cementing and fracturing across multiple zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If dropped balls are used to actuate sliding sleeves for multi-zone fracturing, then the sleeves can be opened to expose fracture zones, but obstructions are formed that require milling out, leading to lost time and reduced productivity
Solution Approach 1:
The invention extracts and removes the problematic dropped balls from the system by using a shifter device that can be lowered on coiled tubing to directly actuate the sliding sleeves. This eliminates the need to mill out obstructions formed by dropped balls, resolving the contradiction between ease of sleeve actuation and fracturing productivity
Solution Approach 2:
The shifter device serves as an intermediary mechanism between the surface operation and the sliding sleeves. Instead of using dropped balls that create obstructions, the shifter device transmits mechanical force through the coiled tubing to directly open the sleeves, eliminating the harmful intermediate step of ball insertion and milling
2Adaptability or versatility
If multiple sets of sliding sleeves are used to access different fracturing zones, then selective zone exposure is achieved, but the wellbore inner diameter is reduced and obstructions must be milled out between zones
Solution Approach 1:
The invention removes the complex obstruction management requirement by extracting the problematic ball-and-milling mechanism from the system. The shifter device provides a cleaner approach that maintains zone selection capability without creating obstructions that reduce wellbore inner diameter
Solution Approach 2:
The shifter device provides a universal solution that can actuate multiple different sliding sleeves along the wellbore through a single device design. This multi-functional approach eliminates the need for different actuation methods for different zones, simplifying the overall system complexity
3Ease of operation
If dropped balls are used to form plugs for sliding sleeves, then the sleeves can be forced to slide downward, but time is lost removing obstructions from the wellbore
Solution Approach 1:
The invention extracts the time-consuming obstruction removal step from the process by eliminating dropped balls entirely. The shifter device directly transmits force to slide the sleeves without creating obstructions that would require milling, thus eliminating the time loss
Solution Approach 2:
The shifter device is lowered on coiled tubing to the target zone before actuation occurs. This preliminary positioning allows direct engagement with the sliding sleeve mechanism, eliminating the need for subsequent obstruction removal operations
Data Source
AI summary
A system and method for fracturing multiple zones along a length of a wellbore during a single run are provided. A single mechanical shifter device may be lowered on coiled tubing to shift open multiple sleeve assemblies set along the wellbore to expose different fracture zones for desired fracturing treatments. The sleeve assemblies may each include a shifting sleeve designed for engagement with the mechanical shifter device. The mechanical shifter device may move the shifting sleeve along the wellbore to collapse a baffle component of the sleeve assembly. Once the baffle is collapsed, an isolation component of the shifter device may engage the collapsed baffle to form a plug through the wellbore. Pressure applied from the surface may push the baffle and a sliding sleeve of the sleeve assembly downward, thereby exposing fracturing ports through the casing of the wellbore. Fracturing applications may then be performed through the ports.